Islamic insurgents have “massacred” some 80 members of Iraq’s Yazidi minority in the country’s north, a Yazidi lawmaker and Kurdish officials said on Friday.

The news came as tribal leaders from Iraq’s Sunni heartland offered their conditional backing for a new government that hopes to contain sectarian bloodshed and stop the advance of militants from the Islamic State of Iraq and Greater Syria (ISIS or ISIL), which now calls itself the Islamic State (IS).

“They arrived in vehicles and they started their killing this afternoon,” senior Kurdish official Hoshiyar Zebari told Reuters. “We believe it’s because of their creed: convert or be killed.”

Report: Iraq's Yazidis seek refuge at Turkish border

A Yazidi lawmaker and another senior Kurdish official also said the killings had taken place and that the women of the village were kidnapped.

Yazidi parliamentarian Mahama Khalil said he had spoken to villagers who had survived the attack. They said the killings took place during a one-hour period.

The resident of a nearby village said an ISIS fighter from the same area gave him details of the bloodshed.

“He told me that (ISIS) had spent five days trying to persuade villagers to convert to Islam and that a long lecture was delivered about the subject today,” said the villager.

“He then said the men were gathered and shot dead. The women and girls were probably taken to Tal Afar because that is where the foreign fighters are.”

A commander of the Kurdish PKK guerilla armed group told FRANCE 24 that at least 80 people had been killed and that another village nearby had also been targeted.

“The whole area is controlled by ISIS and these villages were previously surrounded by ISIS,” reported FRANCE 24’s correspondent in Iraq Adam Pletts.

“There are still other similar villages in the same situation so of course there is still the threat that if those people can’t be rescued from those areas they will suffer the same fate,” he said.

ISIS militants have killed at least 500 members of Iraq’s Yazidi ethnic minority during their offensive in the north, Iraq’s human rights minister told Reuters on Sunday.

Mohammed Shia al-Sudani said the Sunni militants had also buried alive some of their victims, including women and children. Some 300 women were kidnapped as slaves, he added.

A push by ISIS militants through northern Iraq to the border with the Kurdish region has alarmed the Baghdad government, drawn the first US air strikes since the end of American occupation in 2001 and sent tens of thousands of Yazidis and Christians fleeing for their lives.

US President Barack Obama said a first week of air strikes had broken the siege of the northern Sinjar mountain, where Yazidi civilians had been hiding from ISIS jihadists for more than 10 days.

The US carried out more air strikes on Friday, the military said, after receiving reports that ISIS "terrorists were attacking civilians" in the area.

The UN Security Council unanimously adopted a resolution Friday aimed at weakening Islamists in Iraq and Syria with measures to choke off funding and the flow of foreign fighters.

It represents the most wide-ranging response yet by the top United Nations body to the jihadists who now control large swathes of territory in both countries and have been accused of atrocities including summary executions and rape.

The British-drafted measure also placed six Islamist leaders – from Kuwait, Saudi Arabia and other nations – on the al Qaeda sanctions list, which provides for a travel ban and assets freeze.

The six include senior al Qaeda leaders who have provided financing to the Al Nusra Front (ANF) in Syria and Abu Mohammad al-Adnani, the spokesman for the Islamic State in Iraq and Greater Syria (ISIS), which calls itself Islamic State (IS).

British Ambassador Mark Lyall Grant noted that the 15-member council had shown “strong unity” in adopting the resolution to address the IS and Al Nusra threat.

Several European governments, including France, Britain, Germany, the Czech Republic and the Netherlands, have said they will send arms to the Kurds or are considering doing so.

Sunnis say could join new government, fight Islamic State

The crisis prompted embattled Prime Minister Nuri al-Maliki to resign from his post earlier. He is set to be replaced by deputy speaker Haider al-Abadi, who faces the daunting task of uniting Iraq’s various religious communities in the battle against ISIS.

On Friday, one of the most influential Sunni tribal leaders said he was willing to work with Abadi provided a new administration respected the rights of the Sunni Muslim minority that dominated Iraq under Saddam Hussein.

Ali Hatem Suleiman left open a possibility that Sunnis would take up arms against ISIS in the same way as he and others joined US and Shiite-led government forces to thwart an al Qaeda insurgency in Iraq between 2006 and 2009.

Pacifying the vast desert province of Anbar, which forms much of the border with Syria where ISIS fighters also control swathes of territory, is likely to be a particularly pressing concern for Abadi.

Sunni alienation under Maliki, a Shiite, goaded some in Anbar to join the ISIS revolt.

Winning over Sunnis will be vital to any efforts to contain the violence marked by daily kidnappings, execution-style killings and bombings.

Taha Mohammed al-Hamdoon, spokesman for the tribal and clerical leaders, told Reuters that Sunni representatives in Anbar and other provinces had drawn up a list of demands.

This would be delivered to Abadi, a member of the same Shiite Islamist party but with a less confrontational reputation than Maliki.

Hamdoon called for the government and Shiite militia forces to suspend hostilities in Anbar to allow space for talks.

”It is not possible for any negotiations to be held under barrel bombs and indiscriminate bombing, ”Hamdoon said in a telephone interview with Reuters. “Let the bombing stop and withdraw and curtail the (Shiite) militias until there is a solution for the wise men in these areas.”